A battery module having a single cell group in which a plurality of single cells each of which having a positive terminal and a negative terminal which are aligned side by side, and a battery wiring module attached to the group is known as disclosed in Japanese Patent Application Laid-Open Publication No. 2017-27831 (Patent Document 1).
The battery wiring module includes a battery wiring module attached to a front side of the battery module and another battery wiring module attached to a rear side of the battery module.
Each of the two battery wiring modules includes a plurality of bus bars and a flexible printed circuit board.
In the following description, in order to distinguish two battery wiring modules, a battery wiring module attached to a front side of the battery module is referred to as a first battery wiring module. In addition, a battery wiring module attached to the rear side of the battery module is referred to as a second battery wiring module.
The bus bars of the first battery wiring module and the second battery wiring module respectively connect positive terminals and negative terminals of different single cells. For this purpose, each bus bar has two terminal insertion holes into which positive terminals and negative terminals of different unit cells are inserted.
However, one terminal insertion hole is formed in the two bus bars at both ends of the second battery wiring module. One of the two bus bars at both ends is connected to the electrode terminal of the positive electrode. A positive voltage obtained by summing the voltages of the individual cells is outputted from the electrode terminal of the positive electrode.
Further, the other of the two bus bars at both ends is connected to the electrode terminal of the negative electrode. The electrode terminal of this negative electrode is at a ground potential.
Each of the flexible printed circuit boards of the first battery wiring module and the second battery wiring module includes a plurality of voltage detection wirings for detecting the voltage of each cell. The plurality of voltage detection wirings are connected to the bus bars.
As described above, shapes of the bus bars are different between the first battery wiring module and the second battery wiring module.
Accordingly, the voltage detection wirings of the first battery wiring module and the flexible printed circuit board of the second battery wiring module have different shapes.
Therefore, the first battery wiring module cannot be used in place of the second battery wiring module. Conversely, the second battery wiring module cannot be used in place of the first battery wiring module.
As a result, the battery wiring module (wiring section) has a low versatility.